The present invention relates to testing of radio frequency (RF) data packet signal transceivers that rely upon beacon request and response data packets for establishing communication links, and in particular, to enabling rapid estimations of receiver sensitivity of such devices.
Many of today's electronic devices use wireless signal technologies for both connectivity and communications purposes. Because wireless devices transmit and receive electromagnetic energy, and because two or more wireless devices have the potential of interfering with the operations of one another by virtue of their signal frequencies and power spectral densities, these devices and their wireless signal technologies must adhere to various wireless signal technology standard specifications.
When designing such wireless devices, engineers take extra care to ensure that such devices will meet or exceed each of their included wireless signal technology prescribed standard-based specifications. Furthermore, when these devices are later being manufactured in quantity, they are tested to ensure that manufacturing defects will not cause improper operation, including their adherence to the included wireless signal technology standard-based specifications.
For testing these devices following their manufacture and assembly, current wireless device test systems typically employ testing subsystems for providing test signals to each device under test (DUT) and analyzing signals received from each DUT. Some subsystems (often referred to as “testers”) include one or more vector signal generators (VSG) for providing the source, or test, signals to be transmitted to the DUT, and one or more vector signal analyzers (VSA) for analyzing signals produced by the DUT. The production of test signals by a VSG and signal analysis performed by a VSA are generally programmable (e.g., through use of an internal programmable controller or an external programmable controller such as a personal computer) so as to allow each to be used for testing a variety of devices for adherence to a variety of wireless signal technology standards with differing frequency ranges, bandwidths and signal modulation characteristics.
Testing of wireless devices typically involves testing of their receiving and transmitting subsystems. The tester will typically send a prescribed sequence of test data packet signals to a DUT, e.g., using different frequencies, power levels, and/or modulation technologies, to determine if the DUT receiving subsystem is operating properly. Similarly, the DUT will send test data packet signals at a variety of frequencies, power levels, and/or modulation technologies to determine if the DUT transmitting subsystem is operating properly.
One technique includes use of conductive signal paths (e.g., cables to convey the RF signals between the device RF ports and the tester RF ports) to simulate various channel conditions. However, testing a device using conductive signal paths prevents inclusion of its antenna subsystems as part of the test(s), thereby enabling verification of correct operation of a partially assembled device but not of the fully assembled device, i.e., with its antennas. Hence, in order to test a fully assembled device using real-world conditions, radiated signals must be transmitted between the antennas or antenna elements of an antenna array of the device and the antenna(s) of the test system. (Various systems and methods for testing in wireless signal environments are described in U.S. Pat. Nos. 8,811,461 and 8,917,761, and U.S. patent application Ser. Nos. 13/839,162, 13/839,583, 13/912,423, 14/461,573 and 15/197,966, the disclosures of which are incorporated herein by reference.)
While wireless, or radiative, signal environments enable more complete testing at the fully assembled system level, they can also include other or additional challenges. For example, in the case of rapidly growing “Internet of things” (IoT) technology, many IoT devices tend to communicate exclusively via wireless signals and do so with strict, i.e., low, power budgets, which often translates to infrequent communication intervals and limited opportunities to initiate them. Also, with some such, or similar, devices, for communications to occur it is first necessary to “pair” two compatible devices, e.g., by exchanging beacon signals identifying their readiness and abilities to communicate.
For example, Zigbee systems typically require an end-node device and a coordinator device to first be in respective pairing modes of operation. The end-node device sends a beacon request on each of the supported communication channels (e.g., up to 16 for Zigbee) one by one, waits after each beacon request transmission for a predetermined time interval to receive a beacon response, and then moves to the next channel if no response is received. This sequence of beacon request transmissions is done only once or twice, so testing receiver sensitivity of an end-node device is difficult since a tester would traditionally wait on one of the supported channels and then reply with a beacon response if and when a beacon request is received on that channel. Thus, only a single sensitivity power level can be tested, and with the end-node device only doing this once or twice, only one or two sensitivity power levels can be tested.